Q. No.1. \(2:9\)
2. \(1:2\)
3. \(2:3\)
4. \(1:1\)
| 1. | \(\large\dfrac{t_1t_2}{t_1+t_2}\) | 2. | \(t_1+t_2\) |
| 3. | \({\large\dfrac12}(t_1+t_2)\) | 4. | \(\large\dfrac{t_1t_2}{2(t_1+t_2)}\) |
1. \(4:1\)
2. \(1:2\)
3. \(2:1\)
4. \(1:4\)
Which of the following acts as a circuit protection device?
| 1. | Fuse | 2. | Conductor |
| 3. | Inductor | 4. | Switch |
| 1. | \(2:1\) | 2. | \(4:9\) |
| 3. | \(9:4\) | 4. | \(1:2\) |
A filament bulb \((500~\text{W},100~\text{V})\) is to be used in a \(230~\text{V}\) main supply. When a resistance\(R\) is connected in series, the bulb works perfectly and consumes \(500~\text{W}.\) The value of \(R\) is:
| 1. | \(230~\Omega\) | 2. | \(46~\Omega\) |
| 3. | \(26~\Omega\) | 4. | \(13~\Omega\) |
| 1. | \(\dfrac{a^3R}{3b}\) | 2. | \(\dfrac{a^3R}{2b}\) |
| 3. | \(\dfrac{a^3R}{b}\) | 4. | \(\dfrac{a^3R}{6b}\) |
Two cities are \(150~\text{km}\) apart. The electric power is sent from one city to another city through copper wires. The fall of potential per km is \(8~\text{volts}\) and the average resistance per \(\text{km}\) is \(0.5~\text{ohm}.\) The power loss in the wire is:
1. \(19.2~\text{W}\)
2. \(19.2~\text{kW}\)
3. \(19.2~\text{J}\)
4. \(12.2~\text{kW}\)
If the voltage across a bulb rated \((220~\text{V}\text-100~\text{W})\) drops by \(2.5\%\) of its rated value, the percentage of the rated value by which the power would decrease is:
1. \(20\%\)
2. \(2.5\%\)
3. \(5\%\)
4. \(10\%\)
The power dissipated in the circuit shown in the figure is \(30~\text{Watts}\). The value of \(R\) is:
1. \(15~\Omega\)
2. \(10~\Omega\)
3. \(30~\Omega\)
4. \(20~\Omega\)
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